Developing laterite nickel ore leaching residue as sustainable blast furnace charge

A kind of leaching residue generated during high pressure acid leaching of laterite nickel ore is creatively prepared as blast furnace charge for ironmaking. Results show that the briquettes with uniform shape, compressive strength higher than 72.3 N/pellet, and cracking temperature over 400 °C can be obtained by the non-binder briquetting with water content of 12.2 wt.% and pressure of 30 MPa. After preheating at 975 °C for 12 min and roasting at 1225 °C for 15 min, the strength of the roasted briquettes can reach 2815 N/pellet, and the iron grade is 59.27 wt.%. And the sulfur content can be simultaneously reduced to 0.067 wt.%. The obtained briquettes achieve adequate reducibility index, reduction degradation index, reduction swelling index, softening and melting temperatures, which are suitable for blast furnace ironmaking. The results show that this method cannot only effectively treat the leaching residue to reduce the risk of environmental pollution, but also realize the utilization of leaching residue.